CT Scans and Cancer Risks: A Systematic Review and Dose-response Meta-analysis

Abstract

Background There is still uncertainty on whether ionizing radiation from CT scans can increase the risks of cancer. This study aimed to identify the association of cumulative ionizing radiation from CT scans with pertaining cancer risks in adults. Methods Five databases were searched from their inception to November 15, 2020. Observational studies reporting cancer risks from CT scans in adults were included. The main outcome included quantified cancer risks as cancer case numbers in exposed/unexposed adult participants with unified converted measures to odds ratio (OR) for relative risk, hazard ratio. Global background radiation (2.4 mSv per year) was used as control for lifetime attribution risk (LAR), with the same period from incubation after exposure until survival to 100 years. Results 25 studies were included with a sum of 111,649,943 participants (mean age: 45.37 years, 83.4% women), comprising 2,049,943 actual participants from 6 studies with an average follow-up period as 30.1 years (range, 5 to 80 years); 109,600,000 participants from 19 studies using LAR. The cancer risks for adults following CT scans were inordinately increased (LAR adults, OR, 10.00 [95% CI, 5.87 to 17.05]; actual adults, OR, 1.17 [95%CI, 0.89 to 1.55]; combined, OR, 5.89 [95%CI, 3.46 to 10.35]). Moreover, cancer risks elevated with increase of radiation dose (OR, 33.31 [95% CI, 21.33 to 52.02]), and multiple CT scan sites (OR, 14.08 [95% CI, 6.60 to 30.05]). The risk of solid malignancy was higher than leukemia. Notably, there were no significant differences for age, gender, country, continent, study quality and studying time phrases. Conclusions Based on 111.6 million adult participants from 3 continents (Asia, Europe and America), this meta-analysis identifies an inordinately increase in cancer risks from CT scans for adults. Moreover, the cancer risks were positively correlated with radiation dose and CT sites. The meta-analysis highlights the awareness of potential cancer risks of CT scans as well as more reasonable methodology to quantify cancer risks in terms of life expectancy as 100 years for LAR. Prospero trial registration number CRD42019133487.

Computer-assisted Navigation in Lumbar Spine Instrumented Fusions: Comparison of In-hospital and 30-Day Postoperative Complications With Nonnavigated Fusions in a National Database

“…One important long-term risk that deserves mention is the risk of cancer secondary to irradiation from CT scans used for many intraoperative navigation systems either acquired preoperatively or intraoperatively. 18…”

“…One important long-term risk that deserves mention is the risk of cancer secondary to irradiation from CT scans used for many intraoperative navigation systems either acquired preoperatively or intraoperatively. 18 Similar to computer-assisted navigation in total joint arthroplasty, the long-term cost-effectiveness of computer-assisted navigation in spine surgery is not welldefined and is difficult to assess. 19 Factors that may argue against navigation being cost-effective are high acquisition costs, time to train operating room staff, longer surgical times associated with unfamiliarity with its set-up and instrumentation, and maintenance costs.…”

The Role of CT Scan in the Work-Up and Management of Blunt and Penetrating Trauma and Acute Surgical Emergencies - A Focused Literature Review

“…The main concern with the Pan CT is the exposure to radiation which increases the risk of malignancy later in life, however the risk of missed injury outweighs the risk of malignancy later as some injuries results in death if diagnosis is delayed [6,[10][11][12]. In a similar vein the risk of contrast induced nephropathy has recently been dispelled in numerous large studies [13][14][15][16].…”

How Worrying is the Impact of COVID-19 Pandemic on the Population Radiation Risk from Increased Number of CT-Scans?

“…Although this risk in a single patient is negligible, when a crisis such as the COVID-19 pandemic significantly increases the number of CT-scans, the number of cancer cases in the whole population would be remarkable. Based on 111.6 million adult participants from 3 continents (Asia, Europe and America), Cao et al showed in their meta-analysis an inordinately increase (598% increase) in adults cancer risks from CT scans [ 14 ]. The cancer risk was associated with both the radiation dose and CT-sites [ 14 ].…”

“…Based on 111.6 million adult participants from 3 continents (Asia, Europe and America), Cao et al showed in their meta-analysis an inordinately increase (598% increase) in adults cancer risks from CT scans [ 14 ]. The cancer risk was associated with both the radiation dose and CT-sites [ 14 ]. Given this consideration, the increase in the lifetime risk of dying of a cancer linked to CT-scans in Shiraz is estimated by our team and will be discussed in another publication.…”